Rotary latches, for example those used on automobiles, are often configured to operate in two latching stages; a fully latched condition, or primary stage, and a partially latched condition, or secondary stage. In vehicles configured with rotating doors, it is usually apparent when the door is in the secondary stage since the door is visibly ajar. In addition, such vehicles are often configured with auxiliary warning indicia, including for example warning lights or audible indicators signaling that the door is not fully latched. Other vehicles, however, employ sliding doors, which can be slid between closed and open positions. In such vehicles, a double rotary latch, such as disclosed in U.S. Pat. No. 4,835,997 (the entire disclosure of which is hereby incorporated herein by reference), engage opposing strike components in respective open and closed positions. For example, a double rotary latch is shown with a latch member 30 in a fully latched condition in FIGS. 1A-B, in a partially latched condition in FIGS. 2A-B and in an unlatched position in FIGS. 3A-B, with a keeper member 102 engaging the latch member 30 in the latter two positions. Typically, doors configured with such latches do not indicate to the user that the latch is in the secondary stage. For example, it may be difficult to visually discern whether such a sliding door is in a primary or secondary stage.
Exacerbating this problem, it may be possible in some instances for the user to turn a key and associated lock member 41 proximate a lock position (e.g., 90 degrees), even when the latch member 30 is in the secondary stage (see FIGS. 2A-B, cam 81 rotatable by key (not shown)), thereby providing a false sense of security that the lock is fully latched and locked, and providing a false positive indicator that the door is fully latched. This false positive concerning the latched condition of the door is particularly problematic when viewed from the exterior, where the rotational range of the key may be the only indicia concerning the latched condition, thereby leading the operator to assume that the door is latched if it is lockable by way of a full rotation (90°) of the key. If the lock is positioned in a secondary latch stage, then it is easier for the door to be tampered with and opened by unauthorized personnel, even if the lock member 41 partially engages the latch member 30 in a pseudo-lock position as shown in FIG. 2A.